Queuing access to a shared power supply

• US 8,219,258 B1
• Filed: 02/22/2012
• Issued: 07/10/2012
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: eCurv Inc.
• Original Assignee: eCurv Inc.
• Inventors: Almeida, Edison, Stahl, Jonathan O.
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US13/402,283
• Time in Patent Office: 139 Days
• Field of Search: 700/286, 700/291, 700/295, 700/297, 307 34- 35, 307 38- 39, 307/43, 323/234, 323/236, 323/299, 361/81, 361/139, 361/189
• US Class Current: 700/291
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G06N 7/01 Probabilistic graphical models, e.g. probabilistic networks
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/00 Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A method of queuing access to a power supply shared by a set of electrical access points. The access points turn on independently from one another and thus have independent power draws. Each access point has a specific power draw when on. The on state and associated power draw of each of access point is identified, and a load duration curve for each access point is normalized (i.e., combined with load duration curve(s)) from the other access points) into a probability distribution function. The probability distribution function is a normalized load duration curve that thus accounts for a varying set of “operating states” that may occur with respect to the set of access points (when viewed collectively). Each operating state has an associated probability of occurrence. As the operating state of the set (of access points) changes, access to the power supply is selectively queued, or de-queued (if previously queued).

Claims

1. Apparatus, comprising:

at least one hardware processor; and

computer memory holding computer program instructions executed by the hardware processor to provide a method of queuing access to a power supply shared by a set of electrical power access points, the method comprising;

for each access point, identifying a power draw value associated with the access point being in an on state, the power draw value associated with a load duration curve;

normalizing the load duration curves for a set of operating states of the access points to generate a probability distribution function, the probability distribution function having a set of probability thresholds corresponding to the number of operating states, the probability thresholds including at least one threshold representing a particular grade of service (GoS) at which access to the power supply should be queued; and

queuing access to the power supply when, in response to a first change in operating state, the threshold representing the grade of service is met.

2. The apparatus as described in claim 1 wherein the probability distribution function is a transformed Erlang C probability distribution.

3. The apparatus as described in claim 2 wherein the transformed Erlang C probability distribution function models a load duration curve associating a total power demand for the particular grade of service.

4. The apparatus as described in claim 1 wherein at least first and second access points have independent power draws.

5. The apparatus as described in claim 4 wherein the first and second access points are geographically distributed from one another.

6. The apparatus as described in claim 1 wherein one or more appliances are associated with a particular access point.

7. The apparatus as described in claim 1 wherein the step of queuing access to the power supply adjusts a turn-on of an appliance associated with a particular access point.

8. The apparatus as described in claim 7 wherein the turn-on is adjusted by providing the particular access point with an access priority code, the access priority code being a member of a set of access priority codes (APCs) that are provided to the access points including the particular access point, the set of access priority codes defining a relative queuing order of the access points to minimize access point queuing time and power draw collisions from the power supply.

9. The apparatus as described in claim 1 wherein the method further includes de-queuing access to the power supply when, in response to a second change in operating state, the threshold representing the grade of service ceases to be met.

10. The apparatus as described in claim 1 wherein the probability distribution function is re-generated continuously.

11. The apparatus as described in claim 1 wherein the method is implemented as a service on behalf of one or more participating entities.

12. A power demand management system, comprising:

a set of switches, wherein each switch of the set of switches is associated with an electrical power access point, the electrical power access point being one of a set of electrical power access points that provide shared access to a power supply; and

a power router, the power router comprising a hardware element operating software configured to;

for each access point, identify a power draw value associated with the access point being in an on state, the power draw value associated with a load duration curve;

normalize the load duration curves for a set of operating states of the access points to generate a probability distribution function, the probability distribution function having a set of probability thresholds corresponding to the number of operating states, the probability thresholds including at least one threshold representing a particular grade of service (GoS) at which access to the power supply should be queued; and

queue access to the power supply when, in response to a first change in operating state, the threshold representing the grade of service is met.

13. The power demand management system as described in claim 12 wherein the probability distribution function is a transformed Erlang C probability distribution.

14. The power demand management system as described in claim 13 wherein the transformed Erlang C probability distribution function models a load duration curve associating a total power demand for the particular grade of service.

15. The power demand management system as described in claim 12 wherein at least first and second access points have independent power draws.

16. The power demand management system as described in claim 12 wherein one or more appliances are associated with a switch at a particular access point.

17. The power demand management system as described in claim 12 wherein the power router queues access to the power supply by controlling a switch at a particular access point to adjust turn-on of an appliance associated with the switch.

18. The power demand management system as described in claim 17 wherein the turn-on is adjusted by the power router providing the switch at the particular access point with an access priority code, the access priority code being a member of a set of access priority codes (APCs) that are provided to the set of switches including the switch at the particular access point, the set of access priority codes defining a relative queuing order of the set of switches to minimize individual access point queuing time and power draw collisions from the power supply.

19. The power demand management system as described in claim 18 wherein an access priority code (APC) is a function of an end-use service requirement associated with at least one electric appliance associated with the switch that is located at the access point.

20. The power demand management system as described in claim 12 wherein the power router de-queues access to the power supply when, in response to a second change in operating state, the threshold representing the grade of service ceases to be met.

21. The power demand management apparatus as described in claim 12 wherein a switch is associated with a SCADA-compliant device.

22. The power demand management apparatus as described in claim 12 wherein the power router re-generates the probability distribution function continuously.

23. Apparatus associated with an electrical access point, the electrical access point being one of a set of distributed access points that share a power supply, comprising:

at least one hardware processor; and

computer memory holding computer program instructions executed by the hardware processor to provide a method, the method comprising;

providing data identifying a power draw associated with the access point;

periodically receiving an access priority code (APC) for the access point, the APC being one of a set of access priority codes periodically returned to the set of access points to define a relative queuing order of the access points to minimize individual access point queuing time and power draw collisions from the power supply, the set of access priority codes being derived from a probability distribution function having a set of one or more probability thresholds representing grade(s) of service (GoS) at which access to the power supply should be queued or de-queued; and

enabling access to the power supply according to the APC.

24. The apparatus as described in claim 23 wherein one or more electrical devices are associated with the access point.

25. The apparatus as described in claim 24 wherein the one or more electrical devices include a SCADA-compliant device.

26. The apparatus as described in claim 24 wherein the one or more electrical devices include a control device that regulates an electrical operation of a cycling electrical appliance.

27. The apparatus as described in claim 23 wherein the probability distribution function is a transformed Erlang C probability distribution.

28. The apparatus as described in claim 23 wherein the APC sets a relative queuing order for turn-on of an appliance associated with the access point.